#all{
    width:980px;
    margin: 0 auto;
}
#body_head{
    width:980px;
    height:100px;
}
#body_body{
    width:980px;
    height:400px;
}
#foot{
    width:980px;
    height:20px;
}
a{
    text-decoration-line: none;
}